The Germans did a lot of things that people thought were impossible
Like allow a cabal of genocidal loons take over one of the most urbane and cultured nations on the Planet.
As the miniseries said:
"This is the birthplace of Brahms and Beethoven, that can't be happening!"
"Unfortunately none of them are in office."
Like being a war with two of the three largest exonomies on the Plant at the same time, and then declaring an entirely optional war am the LARGEST economy on the Plant (which had as much war making potential as the next three economies combined, and population approaching twice that of "Inner Germany", and was located where it could produce material without the slightest danger of enemy action) .
Like throwing away ~200,000 unrecoverable losses (KIA/MIA/PoW), almost 900 single engine fighters, 120 twin engine fighters, 700+ bombers, 100+ Stuka, 300+ Ju-52 WHILE preparing for and engaging in Operation Barbarossa.
The Reich did indeed do a lot of things the world thought impossible. Thing is, the world thought that because, well, they were impossible, ill-advised under ideal circumstances, and in general monumentally stupid. As a result Germany would up sub-divided for 45 years, had pretty much every reasonably large population center bombed, burned and/or reduced to rubble by artillery fire, permanently lost ALL of East Prussia, and a huge portion of Eastern Germany, suffered mind-numbing casualties, with the population, especially, but not exclusively, in the Eastern Zone treated, well, better than the SS had treated the Slavic populations of the East, but subjected to incredible depredation and humiliations.
Much of the time, not always by any means, but quite often, when "they" say something in impossible, it it worth listening.